Train ticket recomendation

Kindly recommend the most economic way to purchase train ticket for 4 adults arriving CDG on Friday and leaving to Barcelona on Monday. Back to Paris on Sunday and leaving to CDG on Tue.
Greatly appreciate your help.
Linh

For your 2nd stay in Paris from Sunday - Tuesday, likely a Paris Visite 1-3 zone, 2-day ticket, then a single use Paris RER train ticket from wherever you are in Paris all the way to CDG airport, which also includes any Metro rides needed to get you to Gare du Nord for the RER B Paris airport train.